Pneumatic dimension gages



0a. 29, 1968 F. PARRY 3,407,505

PNEUMATIC DIMENSION GAGES Filed June -25, 1965 Fla/ 5 25 4, ,32 $42 Has33 I 35 a 35 INVENTOR. 34 l I p34 FRANK P400! .36 1k 1 -28 BY 2 L29 I vArman United States Patent 3,407,505 PNEUMATIC DIMENSION GAGES FrankParry, Feasterville, Pa., assignor to Moore Products Co., Spring House,Pa., a corporation of Pennsylvania Filed June 25, 1965, Ser. No. 467,0187 'Claims. (Cl. 33172) ABSTRACT OF THE DISCLOSURE A pneumatic dimensiongaging unit having a body with a leaf pivotally mounted with respectthereto, the leaf being positioned by the work to be gaged and having aflat portion extending from a fulcrum over and controlling a nozzle, thelatter portion being spaced from the nozzle in a range such that fluidfrom the nozzle exerts a suction effect on the latter portion.

This invention relates to pneumatic dimension gages, and moreparticularly to an improved gage of simplified construction.

Pneumatic gages have heretofore been proposed, operating upon theprinciple that if a fluid under constant pressure is forced throughupstream and downstream orifices in series with one another, the gaseouspressure in the space between the orifices will be a function of therelative sections of the orifices, and the measurement of the gaseouspressure in the space will indicate the effective area of the dischargeor downstream orifice, as varied by the position of the work withrespect thereto, within certain limits.

'In the prior US. Patent No. 2,881,528 of C. B. Moore there is discloseda gage having a gage element with an improved mounting which has provensatisfactory in use. Difliculties arisewith the gage elements made inaccordance with that patent, particularly in that the bending of theleaf to provide uniformity is difficult to attain so that each gageelement requires calibration and recalibra tion upon substitution of adilferent leaf. The fixed pivot pin also did not permit of adjustment.

In accordance with the present invention an improved gaging element isprovided which is simple in construction, can be quickly assembled anddisassembled for access to the gaging nozzle, can have any desiredamplification, and has a flat movable leaf as a component which issimple to construct and which has improved operating characteristics.

In accordance with the present invention, also, an improved gagingelement is provided which has an adjustable pivotal mounting for theleaf which is free from introduction of oblique force components.

It is a further object of the present invention, also, to provide animproved element having a pivotally supported leaf and in which the leafis removably held in assembled relation in a simple but effectivemanner.

Other objects and advantageous features of the invention will beapparent from the description and claims.

The nature and characteristic features of the invention will be morereadily understood from the following description taken in connectionwith the accompanying drawings forming part thereof, in which:

FIGURE 1 is a diagrammatic view of a pneumatic dimension gage inaccordance with the present invention;

FIG. 2 is a plan view, enlarged, of a gage head or element unit employedin connection with the invention;

FIG. 3 is a longitudinal sectional view taken approximately on the line33 of FIG. 2;

FIG. 4 is a longitudinal sectional view taken approximately on the-line4-4 of FIG. 3; and

FIG. 5 is a transverse sectional view, further enlarged, takenapproximately on the line 5-5 of FIG. 3.

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It should, of course, be understood that the description and drawingsherein are illustrative merely, and that various modifications andchanges can be made in the structure disclosed without departing fromthe spirit of the invention.

Like numerals refer to like parts throughout the several views.

Referring now more particularly to FIG. 1 of the drawings, a pneumaticcomparator gage is there illustrated having a fluid supply connection 10in communication with any suitable source of filtered fluid, such asair, under pressure, which is connected through an adjustable fluidpressure regulator 11 for supplying fluid under constant pressure, andat a selected pressure level, from the supply connection 10. Thepressure regulator 11 is connected by a conduit 12 through a restriction13 which may, if desired, be fixed or manually or automaticallyadjustable as desired.

The restriction 13 is preferably connected to a conduit 14 having aninstrument connection 15 in communication therewith. The instrumentconnection 15 may be connected to any desired instrument I, forindicating, recording, or controlling, and for purposes of illustrationthis is indicated as a pressure gage of the Bourdon dial type with avisible face 16 and a movable indicator pointer 17 for ascertaining thepressure conditions prevailing in the conduit 14.

The conduit 14 is in communication with a gage unit or element 20 shownin more detail in FIGS. 2 to 5, inclusive.

The gage element 20 is illustrated with a specific type of gage circuithaving a pressure readout but it will be recognized that the gageelement 20 may with equal facility be used in conjunction with othertypes of gage circuits in which a fluid pressure or flow is related tothe linear dimension of space.

While the gage element 20 is shown in a particular position, as willhereinafter appear it can be used in any desired position, includingthat shown, inverted from that shown, on either side, pointed down orpointed up, or inclined from any of these positions. The gage element 20preferably includes an elongated body portion 21 having a groove 22along one face thereof, the groove 22 being bounded by an elongatedhorizontal flat face 23 and an inclined flat face 24, and by spaced sidewalls 25. The flat faces 23 and 24 preferably meet intermediate the endsof the groove 22 and the opposite end of the flat face 23 forms a ledge26 which serves as a stop.

The body portion 21 can, if desired, have spaced parallel exterior faces28 and a face 29 therebetween. The body portion 21 can be provided withone or more openings 30 for the reception of the mounting bolts (notshown) for securing the gaging unit at the desired location.

The body portion 21 preferably has, extending from the end thereofcontiguous to the face 24, an extension 31 for connection of the conduit14 and has an interior passageway 32 providing a nozzle which extendsapproximately normal to and terminates at the face 24 and inpredetermined spaced relation, longitudinally considered, with respectto the pivotal mounting hereinafter described.

It will be noted that the nozzle 32 has a flat surface extendingoutwardly from it, consisting of a contiguous section of the face 24,and disposed for an appreciable and major portion of the circumferenceof the nozzle 32. This section of the face 24 extends from the nozzlefor a distance of at least several times the diameter of the nozzle 32,and has a flat surface area surrounding the nozzle 32 at least fivetimes the area of the nozzle 32, to provide a venturi or suction effectas hereinafter referred to.

The body 21 is provided intermediate the ends of the Patented Oct. 29,1968 and contiguous to the side walls with openings 33 hav ing threadedportions 34 to provide adjustable pivot mountings. The openings 33 haveballs 35 carried on threaded plugs 36 for adjusting the positions of theballs 35 above the faces 23 and 24. The plugs 36 are accessible throughthe face 29.

A leaf 40 is provided, which forms the movable portion of the gage unitand is preferably made of a flat strip of relatively stiff material andcan be made as a metal stamping. The leaf 40 has relatively short butwide portion 41 at one end and adapted to be disposed above the nozzle32, side guide projections 42 intermediate its ends which seat looselyin aligned transverse slots 43, and a relatively long but narrow portion44 which is limited in one direction of movement by engagement with theledge 26.

The leaf portion 44 has a contacting projection 45, such as a button orball, secured thereto by soldering or in any other desired manner forengagement with the work to be gaged.

The contacting projection 45 is preferably of ultrahard material sothat, upon repeated engagement with the work, wear will be kept to aminimum.

A cover 46 is provided of sheet metal having a top wall 47, side walls48 adapted to resiliently frictionally engage the side walls 25, and anend Wall 49. The cover 46 serves to retain the leaf 40 in position whengaging fluid is not flowing and, also, tends to protect the leaf 40 andpivot balls 35 from mechanical damage from external objects.

The mode of operation will now be pointed outs If no fluid is suppliedthrough the supply connection 10, or if for any other reason no fluid issupplied to the nozzle 32, the leaf 40 will be retained in the groove 22by the cover 46 in whatever position the body portion 21 is mounted. Theleaf 40 will not necessarily be seated on the balls 35 in the absence offluid flow.

If pressure fluid is supplied through the nozzle 32 such fluid willimpinge on the inner face of the short end section 41, spread sidewisein such a manner as to provide a venturi action or suction effect onthis inner face, and tend to draw the short end section 41 towards theface 24 as permitted by the engagement of the leaf 40 with the balls 35.

If the leaf 40 is not properly seated this venturi action tends to causesuch a seating.

The side guide projection 42 in the slots 43 restrain undesired turningmovement or displacement in the main plane of the leaf 40.

If, now, the long end section 44 is moved towards the face 23 by theengagement of the work to be measured with the contacting button 45 andto an extent determined by the dimension of the work to be gaged, thespace between the inner face of the end section 41 and the face 24 atthe nozzle 32 will be varied and the area for discharge through thenozzle 32 will also be varied. Variation of the latter area will cause achange in the pressure in the space between the restriction 13 and thenozzle 32, and the prevailing pressure in that space can be observed onor utilized at the instrument I, which instrument, with suitablecalibration, can be used for reading dimensions.

With the nozzle 32, end portion 41 and surface 24 functioning in thismanner, no restoring spring is necessary to move the leaf 40 nor is anyholding structure required for the leaf 40 other than the cover 46.

Magnification is, of course, dependent on the ratio of the length of thelever arm along the long end portion 44 from the contacting projection45 to the balls 35 to the length of the lever arm along the'short endportion 41 from the balls 35 to the nozzle 32. While any desired ratiocan be employed within relatively wide limits, a ratio of the order of14 to 1 has been found satisfactory, with the length of the short leverarm of the order of oneeighth of an inch and the length of the longlever arm of the order of one and three quarter inches.

scribed 'obviates problems of shaping of the 'leaf Mite provide afulcrum and also provides a freedom from sidewise displacement ordistortion. The leaf 40 is self aligning on the balls 35.

A very light force is suitable for actuating the contact button 45 andcan be made,'if desired, of theorderof two or three grams. Excessiveforce exerted by'theflworkbn the contact, button 45 cannot damagethe'noz zle 12 and, althrough it is very light, the leaf ,40-is,nevertheless, very rugged, can be easily removed for cleaning andinspection of the gage, and can'even be dropped on the floor withoutupsetting the calibration. The cover 46 can be quickly and easilyremoved and replaced, as desired, being resiliently held in place. I

The gage is particularly useful for gaging dimensions or motions whichoccur at right angles to the longitudinal axis of the age unit.

I claim:

1. Pneumatic gaging apparatus comprising a gaging unit having a bodywith a longitudinal face portion, v

said body having a nozzle terminating at said face portion and with saidface portion extending substantially around said nozzle,

a pair of projections extending above said longitudinal face anddisposed such that the nozzle is out of alignment with a line extendingthrough said projections,

an elongated leaf member having a plane face portion which extendscontinuously over said nozzle and over and in engagement with saidprojections,

the spacing between said longitudinal face portion and said plane faceportion being in a range to set up a suction effect on said plane faceportion of fluid from sad nozzle,

said leaf member having a portion spaced from said projections with apart for engagement with work to be measured.

2. Pneumatic gaging apparatus as defined in claim 1 in which thedistance said projections extend form said face portion being in saidrange.

3. Pneumatic gaging apparatus as defined in claim 1 inwhich said leafmember has sidewise extending guide projections, and I saidbody hastransverse slots in which said guide projections loosely engage.

4. Penumatic gaging apparatus as defined in claim 1 in which saidprojections extending from said face portion have adjusting memberscarried in said body in engagement therewith.

5. Pneumatic gaging apparatus as defined in claim 1 in which the surfacesurrounding the nozzle'has an area at least five times the area of thenozzle.

6. Pneumatic gaging apparatus as defined in claim 1 inwhich a cover isprovided engaging said body and retaining said leaf member againstdislodgment.

7. Pneumatic gaging apparatus as defined in claim in which 2 a cover isprovided engaging said body and retaining said leaf member againstdislodgment.

References Cited UNITED STATES PATENTS 2,594,581 4/1952 Phelps 308-22,881,528 4/1959 Moore 73'37.5 'XR S. CLEMENT SWISHER,A cling PrimaryExaminer.

HENRY ILAssisttmt Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, 0.0. 20231 UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,407 ,505October 29, 1968 Frank Parry It is certified that error appears in theabove identified patent and that said Letters Patent are herebycorrected as shown below:

Column 4, line 18, "age" should read gage line 36, "sad" should readsaid line 42, "form" should read from Signed and sealed this 3rd day ofMarch 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.

